Add nullability annotations

Test: N/A
Flag: EXEMPT adding annotations

Change-Id: I3751cbe73d5a81b00e0bca8c1b6b097edf9b007a
diff --git a/core/java/com/android/internal/protolog/PerfettoProtoLogImpl.java b/core/java/com/android/internal/protolog/PerfettoProtoLogImpl.java
index 2ff8c8c..4264358 100644
--- a/core/java/com/android/internal/protolog/PerfettoProtoLogImpl.java
+++ b/core/java/com/android/internal/protolog/PerfettoProtoLogImpl.java
@@ -930,37 +930,47 @@
     }
 
     private static class Message {
+        @Nullable
         private final Long mMessageHash;
+        @Nullable
         private final Integer mMessageMask;
+        @Nullable
         private final String mMessageString;
 
-        private Message(Long messageHash, int messageMask) {
+        private Message(long messageHash, int messageMask) {
             this.mMessageHash = messageHash;
             this.mMessageMask = messageMask;
             this.mMessageString = null;
         }
 
-        private Message(String messageString) {
+        private Message(@NonNull String messageString) {
             this.mMessageHash = null;
             final List<Integer> argTypes = LogDataType.parseFormatString(messageString);
             this.mMessageMask = LogDataType.logDataTypesToBitMask(argTypes);
             this.mMessageString = messageString;
         }
 
-        private int getMessageMask() {
+        @Nullable
+        private Integer getMessageMask() {
             return mMessageMask;
         }
 
+        @Nullable
         private String getMessage() {
             return mMessageString;
         }
 
+        @Nullable
         private String getMessage(@NonNull ProtoLogViewerConfigReader viewerConfigReader) {
             if (mMessageString != null) {
                 return mMessageString;
             }
 
-            return viewerConfigReader.getViewerString(mMessageHash);
+            if (mMessageHash != null) {
+                return viewerConfigReader.getViewerString(mMessageHash);
+            }
+
+            throw new RuntimeException("Both mMessageString and mMessageHash should never be null");
         }
     }
 }
diff --git a/core/java/com/android/internal/protolog/ProtoLogViewerConfigReader.java b/core/java/com/android/internal/protolog/ProtoLogViewerConfigReader.java
index 38ca0d8..3b24f27 100644
--- a/core/java/com/android/internal/protolog/ProtoLogViewerConfigReader.java
+++ b/core/java/com/android/internal/protolog/ProtoLogViewerConfigReader.java
@@ -3,7 +3,6 @@
 import static android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.GROUPS;
 import static android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.Group.ID;
 import static android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.Group.NAME;
-
 import static android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.MESSAGES;
 import static android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.MessageData.MESSAGE;
 import static android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.MessageData.MESSAGE_ID;
@@ -11,7 +10,6 @@
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
-import android.util.Log;
 import android.util.LongSparseArray;
 import android.util.proto.ProtoInputStream;
 
@@ -38,6 +36,7 @@
      * Returns message format string for its hash or null if unavailable
      * or the viewer config is not loaded into memory.
      */
+    @Nullable
     public synchronized String getViewerString(long messageHash) {
         return mLogMessageMap.get(messageHash);
     }